This invention is generally directed to the field of medical catheter systems and balloons therefor.
Urethral pressure measurements have been used for more than 75 years to assess urethral closure function. Urethral pressure and urethral closure pressure are idealized concepts which aim to represent the ability of the urethra to prevent leakage. So long as the intraurethral pressure exceeds the proximal fluid pressure, urine cannot leak and therefore the subject should be continent. Measurement of urethral pressures requires the introduction of a catheter adapted to perform such measurements. A variety of different techniques are employed to make urethral pressure measurements. Moreover, in the field of urethral impedance planimetry, it is known to measure the elasticity or xe2x80x9ctonusxe2x80x9d of the urethra, the cross-sectional area of the urethra, bladder pressure, abdominal pressure and detrusor pressure. EMGs and imaging data may also be obtained when making such measurements.
One well known technique for assessing a patient""s bladder function is PCA (or xe2x80x9cPressure Cross-Sectional Areaxe2x80x9d) catheter measurement as described, for example, in xe2x80x9cA System for Measurement of Micturition Urethral Cross-Sectional Areas and Pressuresxe2x80x9d by Mortensen et al., Med. and Biol. Eng. and Comput., 1983, 21, 482-488; xe2x80x9cSimultaneous Recording of Pressure and Cross-Sectional Area in the Female Urethra: A Study of Urethral Closure Function in Healthy and Stress Incontinent Womenxe2x80x9d by Lose in xe2x80x9cNeurology and Urodynamics,xe2x80x9d Volume 11, Number 2, 1992; and xe2x80x9cUrethral Pressure Measurementxe2x80x94Problems and Clinical Valuexe2x80x9d by Lose, Scand. J. Urol. Nephrol. Suppl. 207. See also xe2x80x9cUrethral Impedance Planimetryxe2x80x9d presented by Lose et al. at the Medtronic Satellite Symposium, ICS, Tampere, Finland, 2001.
FIG. 1 shows a prior art PCA catheter system 5 comprising catheter body 10, expandable and resilient balloon 20 mounted near distal end 30 of the catheter, balloon channel 40 for introducing saline solution 50 inside and removing saline solution 50 from balloon 20, distal micro-pressure transducer 60 mounted near distal tip 70 of catheter body 10, proximal micro-pressure transducer 65 mounted beneath a portion of balloon 20 and situated proximally from distal pressure transducer 60, and electrodes 80A, 80B, 80C and 80D mounted beneath balloon 20 on catheter body 10. Electrical connectors 9 at the proximal end of catheter system 5 permit electrical connections to be established between electrodes 80A through 80D, transducers 60 and 65, or temperature or other sensors, and external recording and/or analysis equipment (not shown in the Figures).
Cross-sectional area (or xe2x80x9cAxe2x80x9d) is determined by delivering high frequency alternating current between excitation electrodes 80A and 80D and measuring the electrical conductivity of the saline solution inside balloon 20. Balloon 20 is then inflated and deflated incrementally with saline solution during rest and provocative maneuvers, and the drop in voltage between sensing electrodes 80B and 80D is measured. Using the field gradient principles described by Harris et al. in xe2x80x9cElectrical Measurements of Urethral Flowxe2x80x9d in xe2x80x9cUrodynamicsxe2x80x9d, New York, Academic Press, Chapter 34, page 465, cross-sectional area A may be determined. The pressure inside balloon 20 may be increased incrementally to induce dilation, and the resulting pressures may be recorded using the proximal and distal pressure transducers. The resulting pressure response curve is a stress relaxation curve, which may be analyzed to determine the elastic properties of the patient""s urethra. Balloon 20 is preferably fully distensible within the physiological range of the urethral cross-sectional area.
It will now be seen that PCA catheter system 5 comprises several expensive components, most notably distal micro-pressure transducer 60, proximal micro-pressure transducer 65, and electrodes 80A, 80B, 80C and 80D. In addition, catheter system 5 requires the incorporation of balloon channel 40 and the inclusion and mounting of balloon 20. Because the cost of a single PCA catheter system 5 may easily exceed several thousand dollars, it is preferable that at least portions of PCA catheter system 5 be reusable following sterilization.
To date, some PCA catheters have been re-used by mounting disposable balloons on catheter body 10 using sutures or ties 75 that are secured around the proximal and distal ends 85 and 90 of balloon 20. Mounting balloon 20 on catheter body 10 using such manual attachment techniques is time consuming, tedious and does not produce reliable seals between proximal and distal ends 85 and 90 of balloon 29 and the outside diameter of the catheter. What is needed is a PCA catheter system having a disposable balloon which may be readily and quickly mounted on or removed from a catheter body, and which also provides a competent non-leaking seal between the balloon and the catheter when the balloon is filled with saline solution.
Patents and printed publications describing various aspects of the foregoing and other problems, as well as the state of the art, are listed below.
1. U.S. Pat. No. 4,023,562 to Hynecek et al. entitled xe2x80x9cMiniature Pressure Transducer for Medical Use and Assembly Method.xe2x80x9d
2. U.S. Pat. No. 4,191,196 to Bradley et al. entitled xe2x80x9cProfilometry Method and Apparatusxe2x80x9d to Ellis.
3. U.S. Pat. No. 4,545,367 to Tucci entitled xe2x80x9cDetachable Balloon Catheter and Method of Use.xe2x80x9d
4. U.S. Pat. No. 5,385,563 to Gross entitled xe2x80x9cUrodynamic Catheter.xe2x80x9d
5. U.S. Pat. No. 5,449,345 to Taylor et al. entitled xe2x80x9cDetachable and Reusable Digital Control Unit for Monitoring Balloon Catheter Data in a Syringe Inflation System.xe2x80x9d
6. U.S. Pat. No. 5,549,554 to Miraki entitled xe2x80x9cCatheters Having Separable Reusable Components.xe2x80x9d
7. U.S. Pat. No. 5,766,081 to Kreder entitled xe2x80x9cUrethral Pressure Catheter.xe2x80x9d
8. U.S. Pat. No. 5,779,688 to Imran et al. entitled xe2x80x9cLow Profile Balloon-On-A-Wire Catheter with Shapeable And/Or Deflectable Tip and Method.xe2x80x9d
9. U.S. Pat. No. 5,876,374 to Alba et al. entitled xe2x80x9cCatheter Sleeve for Use with a Balloon Catheter.xe2x80x9d
10. U.S. Pat. No. 5,919,163 to Glickman entitled xe2x80x9cCatheter with Slideable Balloon.xe2x80x9d
11. U.S. Pat. No. 5,941,871 to Adams et al. entitled xe2x80x9cCatheter Systems with Interchangeable Parts.xe2x80x9d
12. U.S. Pat. No. 6,021,781 to Thompson et al. entitled xe2x80x9cIntraurethral Pressure Monitoring Assembly and Method of Treating Incontinence Using Same.xe2x80x9d
13. U.S. Pat. No. 6,136,258 to Wang et al. entitled xe2x80x9cMethod of Forming a Co-Extruded Balloon for Medical Purposes.xe2x80x9d
14. U.S. Pat. No. 6,231,524 to Wallace et al. entitled xe2x80x9cPressure Device with Enhanced Fluid Monitoring Features.xe2x80x9d
All patents and printed publications listed hereinabove are hereby incorporated by reference herein, each in its respective entirety. As those of ordinary skill in the art will appreciate readily upon reviewing the drawings set forth herein and upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, at least some of the devices and methods disclosed in the patents and publications listed hereinabove may be modified advantageously in accordance with the teachings of the present invention.
Various embodiments of the present invention have certain objects. That is, various embodiments of the present invention provide solutions to problems existing in the prior art, including, but not limited to, one or more of the problems listed above.
Various embodiments of the present invention have certain advantages, including, without limitation, one or more of: (a) permitting expensive catheter components or catheters to be re-used; (b) reducing the amount of time required to mount a disposable balloon on a catheter; (c) reducing the cost of medical procedures carried out using the balloon of the present invention; (d) increasing the competence and leakworthiness of seals made using the balloon of the present invention; (e) obtaining more reliable and accurate data; (e) providing disposable balloons at reduced cost; and (f) providing balloons having improved mechanical characteristics such as increased tensile strength, increased elasticity and improved resistance to rupture or tear.
Various embodiments of the present invention have certain features, including one or more of the following: (a) a slideable balloon; (b) a balloon carrier configured to engage a catheter and permit a balloon disposed thereon to be slideably moved from the carrier to the catheter; (c) a balloon having proximal and distal ends which slideably engage and seal around a corresponding balloon carrier or catheter; (d) a balloon configured to sealingly engage the outside diameter of a catheter body and prevent saline solution disposed therewithin from leaking therewithout; (e) a disposable balloon formed from an expandable and resilient biocompatible material; (f) a PCA catheter comprising at least one of a plurality of pressure transducers, a plurality of impedance measurement electrodes, and a means for delivering high frequency alternating current between excitation electrodes; and (g) proximal and distal removable sleeves disposed between the inside diameter of the proximal and distal ends of the balloon and the outer diameter of the carrier or catheter.
In one embodiment of the present invention, a catheter system is provided having a disposable balloon, where the system comprises an elongated catheter comprising a first outer diameter, a first proximal end and a first distal end; an elongated balloon carrier having a second proximal end, a second distal end and a second outer diameter, the second proximal end of the carrier and the first distal end of the catheter being configured to permit the first distal end of the catheter to matingly or otherwise suitably engage the second proximal end of the carrier, the second outer diameter of the balloon carrier being similar to the first outer diameter of the catheter, and a disposable balloon formed from an expandable and resilient biocompatible material, the balloon having a lumen disposed between a third proximal end and a third distal end thereof, the lumen having at least a third inside diameter, the second diameter of the carrier and the third diameter of the balloon being configured to permit the balloon first to be slideably mounted onto the balloon carrier and second to be slideably moved from the carrier onto the catheter when the second proximal end of the carrier is matingly or otherwise suitably engaged with the first distal end of the catheter.
In another embodiment of the present invention, a disposable balloon for use in a catheter system is provided, where the system comprises an elongated catheter having a first outer diameter, a first proximal end and a first distal end, an elongated balloon carrier having a second proximal end, a second distal end and a second outer diameter, the second proximal end of the carrier and the first distal end of the catheter being configured to permit the first distal end of the catheter to matingly or otherwise suitably engage the second proximal end of the carrier, the second outer diameter of the balloon carrier being similar to the first outer diameter of the catheter, the balloon being formed from an expandable and resilient biocompatible material, and where the balloon comprises a lumen disposed between a third proximal end and a third distal end thereof, and at least a third inside diameter, wherein the second diameter of the carrier and the third diameter of the balloon are configured to permit the balloon first to be slideably mounted onto the balloon carrier and second to be slideably moved from the carrier onto the catheter when the second proximal end of the carrier is matingly or otherwise suitably engaged with the first distal end of the catheter.
In another embodiment of the present invention, there is provided a method of making a disposable balloon for use in a catheter system comprising an elongated catheter having a first outer diameter, a first proximal end and a first distal end, an elongated balloon carrier having a second proximal end, a second distal end and a second outer diameter, the second proximal end of the carrier and the first distal end of the catheter being configured to permit the first distal end of the catheter to matingly or otherwise suitably engage the second proximal end of the carrier, the second outer diameter of the balloon carrier being similar to the first outer diameter of the catheter, the balloon being formed from an expandable and resilient biocompatible material, the method comprising providing a mandrel having an outside surface defining a desired internal shape of the balloon; providing a container having a biocompatible liquid silicone disposed therein; dipping the mandrel in the liquid silicone to form a coated mandrel; removing the coated mandrel from the liquid silicone;
heating the coated mandrel in an oven to form a heat cured balloon; removing the mandrel and heat cured balloon from the oven, and removing the heat cured balloon from the mandrel.
Methods of mounting a disposable balloon on a catheter using a carrier are also provided.